hammer? Do you mean judgment of the wise?
Previously, you managed with Divine Plea. Now it has been nerfed to 10% of your mana (on top of the 50% healing penalty), so you have to use it wisely (i.e. when you are not healing, or using free heals).
Start using Seal of Insight, it's the old Seal of Wisdom with Seal of Light rolled in.
Finally, you also get a free heal every third Holy Shock. This helps cut down mana usage a bit, along with correct usage of spells (Holy Light instead of Flash of Light or Divine Light).